/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.schema;

import org.apache.lucene.document.Field;
import org.apache.lucene.document.Fieldable;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.index.FieldInfo.IndexOptions;
import org.apache.lucene.search.SortField;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermRangeQuery;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.index.Term;
import org.apache.solr.search.function.ValueSource;
import org.apache.solr.search.function.OrdFieldSource;
import org.apache.solr.search.Sorting;
import org.apache.solr.search.QParser;
import org.apache.solr.response.TextResponseWriter;
import org.apache.solr.response.XMLWriter;
import org.apache.solr.analysis.SolrAnalyzer;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.SolrException.ErrorCode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Map;
import java.util.HashMap;
import java.io.Reader;
import java.io.IOException;

/**
 * Base class for all field types used by an index schema.
 * 
 * @version $Id: FieldType.java 1150848 2011-07-25 18:59:14Z hossman $
 */
public abstract class FieldType extends FieldProperties {
	public static final Logger log = LoggerFactory.getLogger(FieldType.class);

	/**
	 * The default poly field separator.
	 * 
	 * @see #createFields(SchemaField, String, float)
	 * @see #isPolyField()
	 */
	public static final String POLY_FIELD_SEPARATOR = "___";

	/** The name of the type (not the name of the field) */
	protected String typeName;
	/** additional arguments specified in the field type declaration */
	protected Map<String, String> args;
	/** properties explicitly set to true */
	protected int trueProperties;
	/** properties explicitly set to false */
	protected int falseProperties;
	int properties;

	/** Returns true if fields of this type should be tokenized */
	public boolean isTokenized() {
		return (properties & TOKENIZED) != 0;
	}

	/** Returns true if fields can have multiple values */
	public boolean isMultiValued() {
		return (properties & MULTIVALUED) != 0;
	}

	/** Check if a property is set */
	protected boolean hasProperty(int p) {
		return (properties & p) != 0;
	}

	/**
	 * A "polyField" is a FieldType that can produce more than one Fieldable
	 * instance for a single value, via the
	 * {@link #createFields(org.apache.solr.schema.SchemaField, String, float)}
	 * method. This is useful when hiding the implementation details of a field
	 * from the Solr end user. For instance, a spatial point may be represented
	 * by multiple different fields.
	 * 
	 * @return true if the
	 *         {@link #createFields(org.apache.solr.schema.SchemaField, String, float)}
	 *         method may return more than one field
	 */
	public boolean isPolyField() {
		return false;
	}

	/**
	 * Returns true if a single field value of this type has multiple logical
	 * values for the purposes of faceting, sorting, etc. Text fields normally
	 * return true since each token/word is a logical value.
	 */
	public boolean multiValuedFieldCache() {
		return isTokenized();
	}

	/**
	 * subclasses should initialize themselves with the args provided and remove
	 * valid arguments. leftover arguments will cause an exception. Common
	 * boolean properties have already been handled.
	 * 
	 */
	protected void init(IndexSchema schema, Map<String, String> args) {

	}

	protected String getArg(String n, Map<String, String> args) {
		String s = args.remove(n);
		if (s == null) {
			throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
					"Missing parameter '" + n + "' for FieldType=" + typeName
							+ args);
		}
		return s;
	}

	// Handle additional arguments...
	void setArgs(IndexSchema schema, Map<String, String> args) {
		// default to STORED, INDEXED, OMIT_TF_POSITIONS and MULTIVALUED
		// depending on schema version
		properties = (STORED | INDEXED);
		float schemaVersion = schema.getVersion();
		if (schemaVersion < 1.1f)
			properties |= MULTIVALUED;
		if (schemaVersion > 1.1f)
			properties |= OMIT_TF_POSITIONS;
		if (schemaVersion < 1.3) {
			args.remove("compressThreshold");
		}

		this.args = args;
		Map<String, String> initArgs = new HashMap<String, String>(args);

		trueProperties = FieldProperties.parseProperties(initArgs, true);
		falseProperties = FieldProperties.parseProperties(initArgs, false);

		properties &= ~falseProperties;
		properties |= trueProperties;

		for (String prop : FieldProperties.propertyNames)
			initArgs.remove(prop);

		init(schema, initArgs);

		String positionInc = initArgs.get("positionIncrementGap");
		if (positionInc != null) {
			Analyzer analyzer = getAnalyzer();
			if (analyzer instanceof SolrAnalyzer) {
				((SolrAnalyzer) analyzer).setPositionIncrementGap(Integer
						.parseInt(positionInc));
			} else {
				throw new RuntimeException(
						"Can't set positionIncrementGap on custom analyzer "
								+ analyzer.getClass());
			}
			analyzer = getQueryAnalyzer();
			if (analyzer instanceof SolrAnalyzer) {
				((SolrAnalyzer) analyzer).setPositionIncrementGap(Integer
						.parseInt(positionInc));
			} else {
				throw new RuntimeException(
						"Can't set positionIncrementGap on custom analyzer "
								+ analyzer.getClass());
			}
			initArgs.remove("positionIncrementGap");
		}

		if (initArgs.size() > 0) {
			throw new RuntimeException("schema fieldtype " + typeName + "("
					+ this.getClass().getName() + ")" + " invalid arguments:"
					+ initArgs);
		}
	}

	/** :TODO: document this method */
	protected void restrictProps(int props) {
		if ((properties & props) != 0) {
			throw new RuntimeException("schema fieldtype " + typeName + "("
					+ this.getClass().getName() + ")" + " invalid properties:"
					+ propertiesToString(properties & props));
		}
	}

	/** The Name of this FieldType as specified in the schema file */
	public String getTypeName() {
		return typeName;
	}

	void setTypeName(String typeName) {
		this.typeName = typeName;
	}

	@Override
	public String toString() {
		return typeName
				+ "{class="
				+ this.getClass().getName()
				// + propertiesToString(properties)
				+ (analyzer != null ? ",analyzer="
						+ analyzer.getClass().getName() : "") + ",args=" + args
				+ "}";
	}

	/**
	 * Used for adding a document when a field needs to be created from a type
	 * and a string.
	 * 
	 * <p>
	 * By default, the indexed value is the same as the stored value (taken from
	 * toInternal()). Having a different representation for external, internal,
	 * and indexed would present quite a few problems given the current Lucene
	 * architecture. An analyzer for adding docs would need to translate
	 * internal->indexed while an analyzer for querying would need to translate
	 * external-&gt;indexed.
	 * </p>
	 * <p>
	 * The only other alternative to having internal==indexed would be to have
	 * internal==external. In this case, toInternal should convert to the
	 * indexed representation, toExternal() should do nothing, and createField()
	 * should *not* call toInternal, but use the external value and set
	 * tokenized=true to get Lucene to convert to the internal(indexed) form.
	 * </p>
	 * 
	 * :TODO: clean up and clarify this explanation.
	 * 
	 * @see #toInternal
	 * 
	 * 
	 */
	public Fieldable createField(SchemaField field, String externalVal,
			float boost) {
		if (!field.indexed() && !field.stored()) {
			if (log.isTraceEnabled())
				log.trace("Ignoring unindexed/unstored field: " + field);
			return null;
		}
		String val;
		try {
			val = toInternal(externalVal);
		} catch (RuntimeException e) {
			throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
					"Error while creating field '" + field + "' from value '"
							+ externalVal + "'", e, false);
		}
		if (val == null)
			return null;

		return createField(field.getName(), val, getFieldStore(field, val),
				getFieldIndex(field, val), getFieldTermVec(field, val),
				field.omitNorms(), getIndexOptions(field, val), boost);
	}

	/**
	 * Create the field from native Lucene parts. Mostly intended for use by
	 * FieldTypes outputing multiple Fields per SchemaField
	 * 
	 * @param name
	 *            The name of the field
	 * @param val
	 *            The _internal_ value to index
	 * @param storage
	 *            {@link org.apache.lucene.document.Field.Store}
	 * @param index
	 *            {@link org.apache.lucene.document.Field.Index}
	 * @param vec
	 *            {@link org.apache.lucene.document.Field.TermVector}
	 * @param omitNorms
	 *            true if norms should be omitted
	 * @param options
	 *            options for what should be indexed in the postings
	 * @param boost
	 *            The boost value
	 * @return the {@link org.apache.lucene.document.Field}.
	 */
	protected Fieldable createField(String name, String val,
			Field.Store storage, Field.Index index, Field.TermVector vec,
			boolean omitNorms, IndexOptions options, float boost) {
		Field f = new Field(name, val, storage, index, vec);
		if (index.isIndexed()) {
			f.setOmitNorms(omitNorms);
			f.setIndexOptions(options);
			f.setBoost(boost);
		}
		return f;
	}

	/**
	 * Given a {@link org.apache.solr.schema.SchemaField}, create one or more
	 * {@link org.apache.lucene.document.Fieldable} instances
	 * 
	 * @param field
	 *            the {@link org.apache.solr.schema.SchemaField}
	 * @param externalVal
	 *            The value to add to the field
	 * @param boost
	 *            The boost to apply
	 * @return An array of {@link org.apache.lucene.document.Fieldable}
	 * 
	 * @see #createField(SchemaField, String, float)
	 * @see #isPolyField()
	 */
	public Fieldable[] createFields(SchemaField field, String externalVal,
			float boost) {
		Fieldable f = createField(field, externalVal, boost);
		return f == null ? new Fieldable[] {} : new Fieldable[] { f };
	}

	/* Helpers for field construction */
	protected Field.TermVector getFieldTermVec(SchemaField field,
			String internalVal) {
		Field.TermVector ftv = Field.TermVector.NO;
		if (field.storeTermPositions() && field.storeTermOffsets())
			ftv = Field.TermVector.WITH_POSITIONS_OFFSETS;
		else if (field.storeTermPositions())
			ftv = Field.TermVector.WITH_POSITIONS;
		else if (field.storeTermOffsets())
			ftv = Field.TermVector.WITH_OFFSETS;
		else if (field.storeTermVector())
			ftv = Field.TermVector.YES;
		return ftv;
	}

	protected Field.Store getFieldStore(SchemaField field, String internalVal) {
		return field.stored() ? Field.Store.YES : Field.Store.NO;
	}

	protected Field.Index getFieldIndex(SchemaField field, String internalVal) {
		return field.indexed() ? (isTokenized() ? Field.Index.ANALYZED
				: Field.Index.NOT_ANALYZED) : Field.Index.NO;
	}

	protected IndexOptions getIndexOptions(SchemaField field, String internalVal) {
		IndexOptions options = IndexOptions.DOCS_AND_FREQS_AND_POSITIONS;
		if (field.omitTermFreqAndPositions()) {
			options = IndexOptions.DOCS_ONLY;
		} else if (field.omitPositions()) {
			options = IndexOptions.DOCS_AND_FREQS;
		}
		return options;
	}

	/**
	 * Convert an external value (from XML update command or from query string)
	 * into the internal format for both storing and indexing (which can be
	 * modified by any analyzers).
	 * 
	 * @see #toExternal
	 */
	public String toInternal(String val) {
		// - used in delete when a Term needs to be created.
		// - used by the default getTokenizer() and createField()
		return val;
	}

	/**
	 * Convert the stored-field format to an external (string, human readable)
	 * value
	 * 
	 * @see #toInternal
	 */
	public String toExternal(Fieldable f) {
		// currently used in writing XML of the search result (but perhaps
		// a more efficient toXML(Fieldable f, Writer w) should be used
		// in the future.
		return f.stringValue();
	}

	/**
	 * Convert the stored-field format to an external object.
	 * 
	 * @see #toInternal
	 * @since solr 1.3
	 */
	public Object toObject(Fieldable f) {
		return toExternal(f); // by default use the string
	}

	/** Given an indexed term, return the human readable representation */
	public String indexedToReadable(String indexedForm) {
		return indexedForm;
	}

	/** Given the stored field, return the human readable representation */
	public String storedToReadable(Fieldable f) {
		return toExternal(f);
	}

	/** Given the stored field, return the indexed form */
	public String storedToIndexed(Fieldable f) {
		// right now, the transformation of single valued fields like
		// SortableInt
		// is done when the Field is created, not at analysis time... this means
		// that the indexed form is the same as the stored field form.
		return f.stringValue();
	}

	/** Given the readable value, return the term value that will match it. */
	public String readableToIndexed(String val) {
		return toInternal(val);
	}

	/**
	 * Default analyzer for types that only produce 1 verbatim token... A
	 * maximum size of chars to be read must be specified
	 */
	protected final class DefaultAnalyzer extends SolrAnalyzer {
		final int maxChars;

		DefaultAnalyzer(int maxChars) {
			this.maxChars = maxChars;
		}

		@Override
		public TokenStreamInfo getStream(String fieldName, Reader reader) {
			Tokenizer ts = new Tokenizer(reader) {
				final char[] cbuf = new char[maxChars];
				final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
				final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);

				@Override
				public boolean incrementToken() throws IOException {
					clearAttributes();
					int n = input.read(cbuf, 0, maxChars);
					if (n <= 0)
						return false;
					String s = toInternal(new String(cbuf, 0, n));
					termAtt.setEmpty().append(s);
					offsetAtt.setOffset(correctOffset(0), correctOffset(n));
					return true;
				}
			};

			return new TokenStreamInfo(ts, ts);
		}
	}

	/**
	 * Analyzer set by schema for text types to use when indexing fields of this
	 * type, subclasses can set analyzer themselves or override getAnalyzer()
	 * 
	 * @see #getAnalyzer
	 * @see #setAnalyzer
	 */
	protected Analyzer analyzer = new DefaultAnalyzer(256);

	/**
	 * Analyzer set by schema for text types to use when searching fields of
	 * this type, subclasses can set analyzer themselves or override
	 * getAnalyzer()
	 * 
	 * @see #getQueryAnalyzer
	 * @see #setQueryAnalyzer
	 */
	protected Analyzer queryAnalyzer = analyzer;

	/**
	 * Returns the Analyzer to be used when indexing fields of this type.
	 * <p>
	 * This method may be called many times, at any time.
	 * </p>
	 * 
	 * @see #getQueryAnalyzer
	 */
	public Analyzer getAnalyzer() {
		return analyzer;
	}

	/**
	 * Returns the Analyzer to be used when searching fields of this type.
	 * <p>
	 * This method may be called many times, at any time.
	 * </p>
	 * 
	 * @see #getAnalyzer
	 */
	public Analyzer getQueryAnalyzer() {
		return queryAnalyzer;
	}

	private final String analyzerError = "FieldType: "
			+ this.getClass().getSimpleName() + " (" + typeName
			+ ") does not support specifying an analyzer";

	/**
	 * Sets the Analyzer to be used when indexing fields of this type.
	 * 
	 * <p>
	 * The default implementation throws a SolrException. Subclasses that
	 * override this method need to ensure the behavior of the analyzer is
	 * consistent with the implementation of toInternal.
	 * </p>
	 * 
	 * @see #toInternal
	 * @see #setQueryAnalyzer
	 * @see #getAnalyzer
	 */
	public void setAnalyzer(Analyzer analyzer) {
		SolrException e = new SolrException(ErrorCode.SERVER_ERROR,
				"FieldType: " + this.getClass().getSimpleName() + " ("
						+ typeName
						+ ") does not support specifying an analyzer");
		SolrException.logOnce(log, null, e);
		throw e;
	}

	/**
	 * Sets the Analyzer to be used when querying fields of this type.
	 * 
	 * <p>
	 * The default implementation throws a SolrException. Subclasses that
	 * override this method need to ensure the behavior of the analyzer is
	 * consistent with the implementation of toInternal.
	 * </p>
	 * 
	 * @see #toInternal
	 * @see #setAnalyzer
	 * @see #getQueryAnalyzer
	 */
	public void setQueryAnalyzer(Analyzer analyzer) {
		SolrException e = new SolrException(ErrorCode.SERVER_ERROR,
				"FieldType: " + this.getClass().getSimpleName() + " ("
						+ typeName
						+ ") does not support specifying an analyzer");
		SolrException.logOnce(log, null, e);
		throw e;
	}

	/**
	 * Renders the specified field as XML
	 */
	public abstract void write(XMLWriter xmlWriter, String name, Fieldable f)
			throws IOException;

	/**
	 * calls back to TextResponseWriter to write the field value
	 */
	public abstract void write(TextResponseWriter writer, String name,
			Fieldable f) throws IOException;

	/**
	 * Returns the SortField instance that should be used to sort fields of this
	 * type.
	 * 
	 * @see SchemaField#checkSortability
	 */
	public abstract SortField getSortField(SchemaField field, boolean top);

	/**
	 * Utility usable by subclasses when they want to get basic String sorting
	 * using common checks.
	 * 
	 * @see SchemaField#checkSortability
	 */
	protected SortField getStringSort(SchemaField field, boolean reverse) {
		field.checkSortability();
		return Sorting.getStringSortField(field.name, reverse,
				field.sortMissingLast(), field.sortMissingFirst());
	}

	/**
	 * called to get the default value source (normally, from the Lucene
	 * FieldCache.)
	 */
	public ValueSource getValueSource(SchemaField field, QParser parser) {
		field.checkFieldCacheSource(parser);
		return new OrdFieldSource(field.name);
	}

	/**
	 * @deprecated use {@link #getValueSource(SchemaField, QParser)}
	 */
	@Deprecated
	public ValueSource getValueSource(SchemaField field) {
		return getValueSource(field, null);
	}

	/**
	 * Returns a Query instance for doing range searches on this field type.
	 * {@link org.apache.solr.search.SolrQueryParser} currently passes part1 and
	 * part2 as null if they are '*' respectively. minInclusive and maxInclusive
	 * are both true currently by SolrQueryParser but that may change in the
	 * future. Also, other QueryParser implementations may have different
	 * semantics.
	 * <p/>
	 * Sub-classes should override this method to provide their own range query
	 * implementation. They should strive to handle nulls in part1 and/or part2
	 * as well as unequal minInclusive and maxInclusive parameters gracefully.
	 * 
	 * @param parser
	 * @param field
	 *            the schema field
	 * @param part1
	 *            the lower boundary of the range, nulls are allowed.
	 * @param part2
	 *            the upper boundary of the range, nulls are allowed
	 * @param minInclusive
	 *            whether the minimum of the range is inclusive or not
	 * @param maxInclusive
	 *            whether the maximum of the range is inclusive or not
	 * @return a Query instance to perform range search according to given
	 *         parameters
	 * 
	 * @see org.apache.solr.search.SolrQueryParser#getRangeQuery(String, String,
	 *      String, boolean)
	 */
	public Query getRangeQuery(QParser parser, SchemaField field, String part1,
			String part2, boolean minInclusive, boolean maxInclusive) {
		// constant score mode is now enabled per default
		return new TermRangeQuery(field.getName(), part1 == null ? null
				: toInternal(part1), part2 == null ? null : toInternal(part2),
				minInclusive, maxInclusive);
	}

	/**
	 * Returns a Query instance for doing searches against a field.
	 * 
	 * @param parser
	 *            The {@link org.apache.solr.search.QParser} calling the method
	 * @param field
	 *            The {@link org.apache.solr.schema.SchemaField} of the field to
	 *            search
	 * @param externalVal
	 *            The String representation of the value to search
	 * @return The {@link org.apache.lucene.search.Query} instance. This
	 *         implementation returns a
	 *         {@link org.apache.lucene.search.TermQuery} but overriding queries
	 *         may not
	 * 
	 */
	public Query getFieldQuery(QParser parser, SchemaField field,
			String externalVal) {
		return new TermQuery(new Term(field.getName(), toInternal(externalVal)));
	}
}
